This invention pertains to the art of storage containers and more particularly to stainless steel containers utilized by the food industry.
The invention is particularly applicable to refurbishing, reconditioning, or repairing used containers so that they may be used again with a significant savings of construction material and will be described with particular reference thereto. However, it will be appreciated that the invention has broader applications and may be advantageously employed in other container environments and applications.
Stainless steel containers are ideal for products that require high quality protection and where container re-use is anticipated, resulting in long term economic benefits. For example, the food industry, such as makers of syrups, extracts, beverages, alcohols, concentrates, and a variety of other food products, utilize stainless steel containers since stainless steel has no adverse effect on the flavors. Still other industries, such as the chemical industry that requires high purity chemicals and acids to be retained in a container without threat of contamination, utilize these containers. The stainless steel construction is extremely corrosion resistant thereby limiting tainting of the chemical. Still another area of widespread use is for products that may discolor readily. Perfumes, aromatic chemicals, drug products, oils, etc. all are subject to discoloration if contaminated.
The exceptionally long re-use life of stainless steel containers is extremely economical because they deliver years of trouble-free service. These containers are extremely durable even though subjected to extreme wear and tear.
Typically, containers of this type require the elimination of V-shaped crevices that would form between the head or base and the sidewall of the containers. U.S. Pat. No. 2,576,767 issued Nov. 27, 1951 to A'Hearn discloses on effective method and finished container product that resolves this problem. Elimination of these crevices is vital to cleanliness and sterility of the container since otherwise small particles of the container contents may be retained therein even after undergoing known flushing techniques. According to that patent, a groove is formed in the sidewall of the container adjacent the end face of the head or bottom of the container. This groove, deformation, or indentation then defines the region on which a later welding step completes and seals the crevice.
Although containers manufactured according to the method of the A'Hearn patent have met with substantial success, like other containers they are subject to wear and tear over an extremely long period of time. In order to refurbish or recondition these containers, it is necessary to remove the heads and bottoms from the sidewalls thereof so that the containers can undergo a dedenting process.
One known process for securing a new head or bottom to the sidewall of a used container is described in U.S. Pat. No. 3,769,686 issued Nov. 6, 1973 to Massey. As taught in that patent, the head flange is removed, as well as a portion of the sidewall of the container, so that the old head may be removed therefrom. Once the dedenting process is completed, either the old head, or preferably a new one, is inserted into the sidewall and a new groove defined to receive a terminal end of the sidewall. The terminal end is clamped in the groove defined by generally concentric flanges. The clamped arrangement is then bent concomitantly and laterally to cold form the metal. Thereafter, a weld is applied to define a continuous, water-tight joint. Nevertheless, this arragement still results in a crevice being formed between the sidewall and the head of the container.
It has been considered desirable, therefore, to provide a method of refurbishing or reconditioning used containers in a manner that provides a crevice-free container particularly useful for foods, chemicals, and other high quality products.